80% gas furnace versus 90% gas furnace
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- čas přidán 7. 09. 2024
- Today we cover the difference between the 80% gas furnace and the 90% gas furnace.
I go over the installation characteristics.
I also cover the venting characteristics.
Check out my playlist HVAC tips for technicians for more videos like
How to set gas pressure?
How to size ductwork?
How to price HVAC equipment?
#gasfurnace #gasheat #hvactipsfortechnicians
#hvactipsforhomeowners
Love the HE furnance along with the humidifier. The temperature is always steady with no spikes in temperature like my old furnance. I would definitely buy another one. Also, i would recommend buying a water pump instead of using a pvc pipe for drainage. It just looks nicer and the pvc pipe out of the way.
Both furnaces burn 100% of the fuel. If they aren't the mixture is set too rich and the result is incomplete combustion, which will soot up your flue and pollute. The difference is that an 80% furnace will transfer (wait for it) 80% of the heat through the heat exchanger exchanger and into the structure and a 90% efficient will transfer 90% of the heat. That means that lost "waste heat" sent out the flue is 20% and 10% for the respective furnaces I have an 80% furnace in my 14 year old house. It looks basically brand new. My aunt had a 90% furnace that was about the same age. She had to replace her rusted out junk earlier this year. Yah she saved money on fuel, but did she save $4k on fuel in that time and was she able to save that money to buy the replacement furnace? The added complexity and cost just aren't a good economic and possibly not a good environmental tradeoff IMO.
I have not seen a new 80 percent in years.that draft inducer on that 80 looked different then the older ones .great video man,your videos have so much more important information then any of the other hvac youtube guys
Well that makes me feel awesome
Thank you so much for your kind words
I tried to do what I think is best is best without getting too complicated
I just wanna help
I hope you're Chanel blows up man .great video
Thanks Brother You are the man I hope it does too
I second that. I hope the channel blows up too.
Amazon - eBay!
Thanks for the video! I've never heard anyone say "propane is the worst kind of fuel".
I'm in a semi-rural area. All of my customers (mobile home, park model RV, and RV) rely on propane for heat and cooking. I appreciate your info on 90% er's. Eventually even my mobile units will go that direction.
I just don't like the fact that it is non renewable and the company's here Price gouge during the Winter
I think he explained it in the video , sounds like it takes more of it to do the same job of heating than natural gas
@@gusc6785 The BTU per cubic foot of propane, the amount is 2,516BTU, while for natural gas, it is 1,030BTU. Thus as you can see, propane contains more energy than natural gas-more than twice. And in an hour, you will use approximately 2.4 more cubic feet of natural gas than propane.
@@TaddyDigest are you trying to argue that natural gas is a renewable and somehow better than propane? Propane contains 2.4 times as much energy per cubic foot so you have to use less. Additionally both propane & natural gas are fossil fuels either extracted from oil refining or directly from the ground.
@@brhop1982 thank you
By the time you factor in the initial costs, actual lifespan, and maintenance costs of a 90% furnace, I doubt most would ever recover the costs. The safe bet is still with an 80% furnace.
I might consider a high efficiency furnace if I lived up north but where I live in the south, it doesn’t really makes sense to install one. In fact, I have never seen a high efficiency furnace in any home where I live but I hear that some custom home builders are installing them now.
I hear that Democrats want to outlaw 80% gas furnaces but that would be a huge mistake in my opinion.
This war against gas appliances really needs to stop. It really hurts lower income people the most. This push towards efficiency really increases the prices so that consumers can rarely recover costs through lower energy bills. In the case of furnaces and water heaters, high efficiency models are much more expensive, less reliable, and require a lot more maintenance.
@@picklerix6162 The more I have learned since writing this response, the more I believe I would never buy a high efficiency / condensing furnace anywhere. They have a much higher risk of breakdown and over the past year, the quality of manufacturing has gone way down. 80% efficiency are much easier to fix and who want's their furnace to break down where it is COLD! Our new construction has an 80% efficiency furnace and the blower broke down. Ironic it was not the motor, but the mother board that controls the motor speed.
Thanks
There such a thing as "good enough". I have elected to install a new 60k btu , 80% furnace in my home to replace the existing 80k btu. Calculations show that the old furnace was too big for my 1600 sf home here in Portland, Oregon's relatively mild climate. The payback period here would not justify the more expensive units. Gas and electric are relatively inexpensive in the Pacific North-West. Of course, that could change, but I doubt I would be in this house for more than 10 years maximum. The new furnace requires minimal alterations to install, and in general, less high tech to go wrong and cost more to repair in the future.
I’m not sure where you’re buying B Vent pipe but I paid $29.97 for a 5 foot piece of 4” B Vent pipe at Home Depot when I installed my 80% furnace. I’m pretty sure that contractors can get a better price than that at the supply house.
My brother first of all thanks for everything. Thanks for this knowledge I am from Michigan. I need your help. Please let me know which one is better because I need to install new furnace at my home and it is only $1000 difference which one you prefer. 80% or 90%Please help me. I need your opinion.
Excellent video with a lot of useful information. I currently have a 100,000 btu gas furnace which I need to replace due to 3.5 ton compressor going bad along with 400sqt addition which bring the house to around 1800sqt with 10 big windows. What size btu furnace and compressor would you ruffly recommend for the size house. I think the unit is 28+ years old.
100k furnace for sure
Great Info, Thanks
Glad it was helpful!
Knoxville TN
thanks bro, down here in the florida swamp
Thanks so much, I do have a Trane X90 80,000BTU single stage and my house is a high ceiling and colonial style 2500sqf, one of my rooms upstairs has low heat, do you think 2 stage furnace will be good for me
6 pm
Oklahoma City
On a multi stage furnace, how does it know at what setting, high, low or variable? I'm not in the HVAC business but am looking at a furnace replacement and would like to make an informed decision. Thank you.
Electric wall heaters are way more cost effective over the lifetime of the home. They last way longer and after the initial installation they cost only $200 to completely replace. No hvac gouging required
The fact is that 10% extra energy saving adds up over time after 20 plus years the only guaranteed thing is fuel cost only go up
Great stuff
I joined. Question; what would require that a high efficiency furnace go from 2” exhaust to 3” pipe? The install manual lists both with :” allowing longer runs.
I certain amount of length in feet of pipe and/or elbows or turns would be the determining factor in a fresh air or exhaust pipe going from 2. Inch to three inch
I have a builders grade York furnace installed in my attic. That freaking condensate line freezes every winter. I had to run a pipe heater wire. So mad at the builder for not knowing don’t use 90% in attics
90% furnaces in attics in cold climates is not recommended
I'm getting ready to replace my 1987 Rheem furnace with a new 80% efficiency furnace. Question: My furnace already has ductwork leading to the chimney through which it vents. The existing exhaust ductwork is single-walled. Couldn't I just keep the single-walled ductwork for the new 80% furnace. So far I've been told that "we always replace with new double-walled ductwork. My question is WHY? Does IRC code require it with an 80% furnace? My furnace is in my basement, so it's perfectly safe to have single-walled ductwork there. It's only about 3 feet to the chimney.
10%!
I think I got screwed by my HVAC guy. He pulled out a 97% and installed a 80%. We of course went with a cheap bid not knowing what we were getting. The AC is pretty efficient (comparing to our old 40 year model) but our heat bill is so high. In the winter, we just used 165 therms. Question: Should I get rid of it and install a high efficiency 90s furnace? Since I just got it 3 years ago, I'm going to have to wait a long time for it to die. I wonder if it's worth the investment from now. Thanks for the video.
HOw old was your 97% furnace?
@@znrctrnn hmmm. Don’t know. It didn’t look old. The AC condenser was from the 70s but the furnace looked fairly decent. He probably sold it to someone else. 😂
@@sophiathe380sl It is unethical to sell you a 80 when you had a 97 and not tell you that you will have more gas usage. Care to mention the name of the company?
@@znrctrnnlol unethical in what way ?
Good windows and doors will save more energy than any difference from 80 to 90 furnace, plus the savings fom better longevity of 80 over the rusty 90.
How many btu max for 4”, 5”, 6” metal flue and how many btu for 2” pvc and 3” pvc
I installed a 95% furnace in my home three years ago. It has already paid for itself in savings over my old 80% furnace.. My heating bill is much lower.
I too have a 95% VS that was installed 16 years ago and still going. I’ve replaced the igniter once, the pressure switch assembly once (recall) and that DC blower has run continuously the whole time. Consistent temp and humidity year round. I spent the extra money for efficiency and stability and would do it again.
@@joeyoungs8426 I should say that I completely understand why it may not be financially advantageous for some people to buy a 95% furnace. If they buy through an HVAC company that marks the furnace up 200 to 300 percent as many do and then charge thousands of dollars to do the install and on top of that sell them an expensive warranty package...It could take decades for the gas savings to pay off such a huge investment.
I bought my furnace on Ebay for about 2 thousand dollars and I did the install myself. I had a little HVAC experience in two of my former jobs before I retired, so I was not afraid to take on the task and learn what I still needed to know before doing the complete install solo. I live at over 9000 feet elevation so I had to calculate the BTUs needed when the furnace is derated for the altitude and I also had to calculate the orifices size to suit the altitude as well. It was not a simple install and I did have to buy some tools like a manometer and other calibration equipment as well as some plumbing for the condensate drainage and neutralization into my sewerage system.. For the furnace and everything included I spent about $2500. for all I needed.
I know for a fact that people living in my area with a similar sized home have spent more than four or five times that much money for a similar unit and install from our local HVAC companies. It will take those people a lot longer before they begin to pay back their investment from their gas savings.
I am now well into my fourth heating season with my 95% furnace. without any problems and just a little maintenance, like cleaning and filter changes. My efficient furnace has already paid off my investment over what it would be if I had bought an 80% furnace.
It really pays to be able to learn to help yourself and not have to rely on the money gouging dishonest professionals.
Difference between >>>80% furnace versus 90% furnace
Nonsense...You were taken for a ride.
What about if you use Natural Gas to heat with? Is a High Efficiency Furnace better or a Regular Furnace better. Heat Pump or no heat pump. We live in South West Pennsylvania.
It depends on the temperatures that you experience and how long.
It depends on where you're going to install the furnace in A crawl space or attic. And what you're insulation is
@@TaddyDigest In our finished basement. Stone block/cement block wall. Concrete floor.
What's your opinion on AirTemp Brand High Efficiency Gas Furnace??
I've never heard of air temp send me the link to the equipment.
90% furnace has 2 heat exchangers
I just replaced my Central Air system. I was told by the tech that he was replacing 90% systems that were only 4 years old, due to system failure. It sound that your more interested in money than the customer.
Ninety percent systems last ten fifteen twenty years
I don't know what hes talking about.
Then why did my tech warn me about the short life of 90% furnace. We had to wait 3 day for the 80% furnace to arrive.. He was more inserted in me as a customer than money. Or is more experienced
@Ckmi1 Don't believe everything you are told
I sell four hundred units a year
I have ninety percent furnaces that are still in the field working and there are hundreds of them that are fifteen years old.
I replaced one the other day that was on video and it was 20 years old.
You mentioned that the 90% furnace will freeze 🥶 what happens when it freezes? I live in utah and we get alot of snow here and it gets cold. I was considering to install a 90% in a closet, now I’m concern about the freezing 🥶. The hvac told me that he could also install a 80% furnace but in the attic space, is that safe??
It depends on if your attic space is either one Conditioned or insulated with like foam insulation
@@TaddyDigest the attic has White Fibre Glass Blowing, it doesn’t have foam insulation in the walls. Why?
The high efficiency furnaces require a drain line that can freeze up if the furnace is located in a space that drops below freezing like most attics.
I have an 80 natural gas furnace. We have to run a humidifier in the winter because the furnace will drop the humidity in the house down to the mid-20s. So a 90% would just make this issue worse right?
A 90% efficient furnace won’t take any extra moisture out of your air. Generally the combustion air is taken from outside and then exits through the flue pipe. So this creates a completely separate air path from the air path in your ductwork. However, a humidifier is still a good idea, because the more moisture in the air, the more energy you can store. And then there are other benefits to the wood in the house when you keep the moisture up.
I have a question we currently have a 90% which is getting old, I would like to purchase a 80% while prices are affordable and when my furnace goes out I have a backup, my question is I live in a split level house the furnace is in a room close to the exterior wall. Our current pvc exhaust goes up 4 foot to the ceiling over 6 foot to the outside, can I in the future put the 80% in and use the double vent exhaust doing the same as the 90% up 4 foot over 6 foot to the outside??
Thanks Dan
Hey Dan yes you can do the same thing. But it half it's to go above the ridge of the roof.
I mean side of one side of the roof.
What a salesperson go with you 80% let's break let's parts to go bad? I originally had an 80% it's lasted 43 years. I've had three 90% efficient everyone don't even last 10 years and they start breaking down on you after 5!
You might want to check your sentence I couldn't really understand
Jaime-Sedona
I have a 95% high efficiency furnace. It's a piece of crap. Always has issues. Condensing furnace is delicate. If it isn't leaking it has some sort of other issues. My 80% furnace went 20 years with out issues. My new 95% furnace like everything made today is just crap.
Just like today's cars. More complex, built in layers, full of cheaply produced components, obsolete in 20 years, and not serviceable by the average Joe with some common sense and a tool box. It's today's reality.
Spot on my friend
If I move to Tennessee from Texas would you hire me ? 4 years of experience
I am not currently hiring
Do I need to change my double wall to pvc since I put in a 90% in place of my 80? Or can I leave it
yes change to pvc
A metal flue will rust and corrode through in less than one heating season. Because the water condenses out of the exhaust and that water is also acidic. For that reason PVC is required for high efficiency furnaces.
So 1st and 2nd stage furnaces are really just 1/2 and 1 stage according to the WC gas pressures they use. I thought maybe 1st stage was 3.5 in and 2nd stage was double that at maybe 7 in WC. So technically 1st stage is only half of the heat that you would get on a normal 1 stage furnace.
Am i wrong?
No you're right
You are absolutely correct
3 and a 1/2 inches of water column on natural gas would be high stage and that would be a 100%
@@TaddyDigest
Thank you, i actually never really thought about that until now.
Well I'm glad you watched the video
I'm also glad that I did this video
Thank you
2nd on natural is 3.5.
2nd on lp is 10
First is half on both .you cannot run 7wc or 20wc manifold pressure on any equipment i have ever seen.
Yup absolutely Agree Thank you Richard
The Price of Natural Gas is Super Low and Always Will Be. Oil Companies Do Not Know what do with all of It. 80% all the Way.
it is disingenuous to say that the 90% is going to a little bit more expensive. It is also impossible to know if it is as much as 1% more efficient unless you are using bottled fuel. The idea of having a furnace in your home is to keep you warm in freezing environments. why even build a furnace that vents water? Is that SCIENCE. Keep it.
You create the most btu's during change of state. 970 btu's are created by creating 1pound of condensate.this is why category 4 furnaces make water
That’s not true to say you can’t accurately get the efficiency 1%, you can do combustion analysis and adjust the gas valve to meet the efficiency rating
York and Samsung all the way am I right?!
All the way
Great video. Thanks for the info. Our heat pump just went on the Fritz and we were told we needed a new one. I'm strongly thinking about getting a natural gas furnace instead as I hated our old heat pump. It was noisy and didn't give us toasty heat we need here in Canada. Can the gas furnaces you showed us be mounted horizontally in a 4 foot crawl space? Also do gas furnaces help dry out your home. We have a huge humidity problem in our house . Thanks
Glad it was helpful!
That would be a massive step backwards. Newer heat pumps are extremely efficient and produce heat down to -30 celcius (Mitsubishi Zuba). Government incentives are big for heat pumps right now. Gas is not the way to go now.
@@mathieur-w1205 Some, including myself, would disagree with that. Heat pumps as primary heat source makes one grid (or massive generator) dependent. Of course government offers incentives. It helps keep us reliant on them for our survival.
@@TaddyDigest hello tad, Im a hvac tech. I’ve seen have a very old 80 percent that only has a old board for a thermostat, gas valve, flame sensor and igniter. Small Flame comes on every now and then but flames won’t kick on nor will it spark/ignite. Need help tad or techs